Conventionally, much research on forming of a fine flow channel structure, and synthesis, separation, analysis, and the like of fluid samples in the flow channel has been conducted, and a micro TAS (Total Analysis System) is widely known in its technical field. As a method of forming a fine flow channel structure, a method of joining two plates to form a flat flow channel plate is generally known. One of the flow channel plates has a groove to be a fine flow channel formed on its surface, and the other plate has through holes formed at positions corresponding to the end portions of the fine flow channel as an outlet and an inlet of the fine flow channel, and the plates are joined with the surface on which the groove is formed arranged on the inside.
To transfer a fluid sample into and out of such a flow channel plate, high air tightness or liquid tightness has to be secured at the time of connecting an outer flow channel to the inner flow channel of the flow channel plate so that there is no leakage of the fluid sample. When connecting an outer flow channel to the inner flow channel of the flow channel plate, it is desired that, in addition to there being no leakage of a fluid sample from the connection section, the dead volume at the connection section is small. For example, in the case of using the flow channel plate as a column for separation/analysis such as a gas chromatography or a liquid chromatography, if there is a great dead volume at the connection section especially at the outlet side, the peak shape of the chromatogram is affected, and the analysis result is impaired.
As methods of preventing leakage of a fluid sample at the connection section, and of reducing the dead volume at the connection section, a method of pressing, against a flow channel plate main body, a connection block to which a capillary or the like which is an outer flow channel may be connected by using a ferrule, with a gasket sandwiched between the connection block and the flow channel plate (see Patent Document 1), and a method of joining a connection block directly to a flow channel plate main body (see Non-Patent Document 1), may be cited.